US11966196B2 - Toner and method for producing toner - Google Patents

Toner and method for producing toner Download PDF

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US11966196B2
US11966196B2 US17/205,702 US202117205702A US11966196B2 US 11966196 B2 US11966196 B2 US 11966196B2 US 202117205702 A US202117205702 A US 202117205702A US 11966196 B2 US11966196 B2 US 11966196B2
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toner
particle
concave portions
dispersion
toner base
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US20210302851A1 (en
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Noritaka Toyoizumi
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Canon Inc
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Canon Inc
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08706—Polymers of alkenyl-aromatic compounds
    • G03G9/08708—Copolymers of styrene
    • G03G9/08711—Copolymers of styrene with esters of acrylic or methacrylic acid
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0802—Preparation methods
    • G03G9/0804—Preparation methods whereby the components are brought together in a liquid dispersing medium
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0802—Preparation methods
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0819—Developers with toner particles characterised by the dimensions of the particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0821—Developers with toner particles characterised by physical parameters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0825—Developers with toner particles characterised by their structure; characterised by non-homogenuous distribution of components
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0827—Developers with toner particles characterised by their shape, e.g. degree of sphericity
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08755—Polyesters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08764—Polyureas; Polyurethanes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08742—Binders for toner particles comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G03G9/08768—Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08775—Natural macromolecular compounds or derivatives thereof
    • G03G9/08782—Waxes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/09307—Encapsulated toner particles specified by the shell material
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/09307—Encapsulated toner particles specified by the shell material
    • G03G9/09314—Macromolecular compounds
    • G03G9/09321—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/09307—Encapsulated toner particles specified by the shell material
    • G03G9/09314—Macromolecular compounds
    • G03G9/09328—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/093—Encapsulated toner particles
    • G03G9/09392—Preparation thereof

Definitions

  • the present disclosure relates to a toner used in a recording method that utilizes an electrophotographic method, an electrostatic recording method, or a toner jet system recording method, and relates to a method for producing the toner.
  • Japanese Patent Application Laid-open No. 2015-11077 discloses a toner in which the surface of a toner core particle is coated by a shell layer formed of a resin that contains a unit derived from monomer for a thermosetting resin and a unit derived from a thermoplastic resin.
  • Japanese Patent Application Laid-open No. 2015-141221 discloses a toner that exhibits both an excellent fixing performance and an excellent storability.
  • a shell layer is formed on the surface of a toner core, and in this shell layer, a plurality of concave portions, which each expose the core, are formed.
  • Japanese Patent Application Laid-open No. 2017-116712 discloses a toner having an excellent storability and an excellent low-temperature fixability.
  • This toner has a plurality of concave portions in the surface of a toner core, and has a shell layer that is present on the surface region of the toner core in both the regions within the concave portions and the regions outside of the concave portions.
  • Japanese Patent Application Laid-open No. 2015-1412221 it is thought that the hardness distribution of the toner particle is controlled by the formation, in the shell layer, of a plurality of concave portions that expose the core.
  • the number of concave portions in the shell layer is insufficient and that there is room for improvement in the low-temperature fixability similarly to the toner described in Japanese Patent Application Laid-open No. 2015-11077.
  • Japanese Patent Application Laid-open No. 2015-141221 does not address the storage stability in severe environments in which temperature and humidity undergo sharp variations.
  • Japanese Patent Application Laid-open No. 2017-116712 has neither a satisfactory storability nor a satisfactory durability. It has been found that in the toner according to Japanese Patent Application Laid-open No. 2017-116712, the shell layer is present in both the regions within the concave portions and regions outside of the concave portions, however, the coverage of the toner particle is not uniform and that many regions where the toner core is exposed over a broad range are present. This has been presumed to result in the unsatisfactory storability and unsatisfactory external additive retention. In addition, Japanese Patent Application Laid-open No. 2017-116712 does not address the storage stability in severe environments in which temperature and humidity undergo sharp variations.
  • the present disclosure has been pursued considering the above problem and provides a toner that exhibits an excellent low-temperature fixability, an excellent storability in severe environments, and an excellent durability, and also provides a method for producing the toner.
  • the toner of the present disclosure is a toner comprising a toner particle that comprises a toner base particle and an outermost layer present on a surface of the toner base particle, the toner base particle containing a binder resin wherein
  • the method for producing a toner of the present disclosure is a method for producing a toner comprising a toner particle that comprises a toner base particle and an outermost layer that covers a surface of the toner base particle, the toner base particle containing a binder resin the production method comprising:
  • a toner and a method for producing a toner that exhibit an excellent low-temperature fixability, an excellent storability in severe environments, and an excellent durability can be provided.
  • the FIGURE is a heat cycle time chart.
  • the toner of the present disclosure is a toner comprising a toner particle that comprises a toner base particle and an outermost layer present on a surface of the toner base particle, the toner base particle containing a binder resin wherein
  • the present inventor carried out investigations and found that when an outermost layer is present on a toner particle, the area where the toner base particle is exposed at the toner particle surface is made small, toner base particle-to-toner base particle contact between toner particles is suppressed, and the storability in severe environments is improved. It was also found that the charging characteristics are improved by increasing the area over which the outermost layer is present on the toner particle surface.
  • the low-temperature fixability can be impaired when the area over which the outermost layer is present on the toner particle surface is increased.
  • the heat stability of the toner particle assumes an increasing trend when an outermost layer is present on the surface of the toner base particle. Due to this, the outermost layer exercises a large effect on the thermal properties of the toner base particle when the area over which the outermost layer is present on the toner particle surface is increased, and a reduction in the low-temperature fixability exhibited by the toner base particle can then occur.
  • the present inventor discovered that, by having the outermost layer of the toner base particle have concave portions, the configuration of the outermost layer and toner base particle at the toner particle surface could be better controlled than heretofore and the severe environment storability could be made to coexist with an excellent low-temperature fixability and durability.
  • a concave portion in the toner particle surface denotes a region where the toner base particle is exposed or a region where the thickness of the outermost layer becomes thin, and is presumed to function to reduce the area over which the outermost layer is present on the toner particle surface.
  • a novel effect was also found: when concave portions are formed in the toner particle surface, the external additive is then fixed in the concave portions and a trend of stabilization of the charging performance and flowability is then displayed even during long-term use.
  • the present inventor thought that, by controlling the size and number of the concave portions, the severe environment storability could be made to coexist with a suppression of the impairment of the low-temperature fixability, and thus achieved the present disclosure.
  • T (nm) is an average thickness of the outermost layer in analysis of a cross section of the toner particle as observed with a transmission electron microscope
  • n represents a number of the concave portions that satisfy formulas (1) to (3) below per 1 ⁇ m 2 of the surface of the toner particle, “n” is from 30 to 200.
  • the number of the concave portions “n” is less than 30, low-temperature fixability is not obtained and storability in severe environments is not obtained. In addition, storability in severe environments is not obtained when the number of the concave portions “n” is larger than 200. From the standpoints of the low-temperature fixability, durability, and storability in severe environments, the number of the concave portions “n” is preferably from 60 to 180 and is more preferably from 100 to 150.
  • the number of concave portions “n” can be controlled through the concentration of dispersing agent particles that are attached to the toner base particle during formation of the outermost layer and through the heating temperature during formation of the outermost layer. Specifically, the number of the concave portions “n” increases with an increase in the concentration of the dispersing agent particles and with an increase in the heating temperature during formation of the outermost layer.
  • the long diameter A of the concave portions is preferably from 50.0 nm to 200.0 nm and is more preferably from 80.0 nm to 170.0 nm.
  • the short diameter B of the concave portions is preferably from 10.0 nm to 70.0 nm and more preferably from 20.0 nm to 45.0 nm.
  • the low-temperature fixability tends to be more improved when the long diameter A of the concave portions is at least 50.0 nm.
  • the low-temperature fixability also tends to be more improved when the short diameter B of the concave portions is at least 10.0 nm.
  • the storability in severe environments tends to be more improved when the long diameter A of the concave portions is not more than 200.0 nm.
  • the storability in severe environments also tends to be more improved when the short diameter B of the concave portions is not more than 70.0 nm.
  • the long diameter A of the concave portions and the short diameter B of the concave portions can be controlled through the long diameter and short diameter of the dispersing agent particles that are attached to the toner base particle when the outermost layer is formed, and the long diameter and short diameter of these dispersing agent particles can be controlled through, for example, the reaction temperature and shear conditions during production of the dispersing agent particles. Specifically, a higher reaction temperature and stronger shear conditions during production of the dispersing agent particles tend to provide a smaller long diameter A and short diameter B of the concave portions.
  • the following formula is preferably satisfied by the average thickness T of the outermost layer in analysis of the toner cross section as observed with a transmission electron microscope (also indicated by TEM in the following), and by the depth D of the concave portions as obtained by measurement of the concave portions on the toner particle surface, using a scanning probe microscope, from the outermost surface of the outermost layer toward the center of the toner particle.
  • This D is more preferably from 0.8 ⁇ T (nm) to 1.1 ⁇ T (nm).
  • D is at least 0.7 ⁇ T
  • the area of the toner base particle present in the concave portions is then large, and as a result the low-temperature fixability tends to be more improved.
  • D is not greater than 1.5 ⁇ T
  • the concave portions are then not too deep and as a result the occurrence of strain in the surface of the outermost layer and the occurrence of burial of the external additive are suppressed and the durability tends to be more improved.
  • the concave portion depth D can be controlled, for example, through the concentration of the dispersing agent particles that are attached to the toner base particle when the outermost layer is formed, and through the amount of addition of the material that forms the outermost layer. Specifically, the concave portion depth D assumes an increasing trend as the concentration of the dispersing agent particles increases and as the amount of addition of the material that forms the outermost layer increases.
  • N represents a number of the concave portions that satisfy both formulas (5) and (6) below per 1 ⁇ m 2 of the surface of the toner particle (such concave portions are also referred to in particular as oversized concave portions in the following), “N” is not more than 10. This N is more preferably not more than 5. In addition, the number of the oversized concave portions “N” is preferably at least 0. Any combination of these numerical value ranges may be used. 250.0 ⁇ a (5) 100.0 ⁇ b (6)
  • the number of the oversized concave portions “N” having a long diameter a greater than 250.0 nm and a short diameter b greater than 100.0 nm can be adjusted through, for example, the concentration of the dispersing agent particles that are attached to the toner base particle during formation of the outermost layer. Specifically, as the concentration of the dispersing agent particles declines, a declining trend is assumed by the number of the oversized concave portions “N” having a long diameter a larger than 250.0 nm and a short diameter b larger than 100.0 nm.
  • the average thickness T (nm) of the outermost layer is preferably from 5.0 nm to 100.0 nm.
  • the durability and the storability in severe environments tend to be more improved when the average thickness T (nm) of the outermost layer is at least 5.0 nm.
  • the low-temperature fixability tends to be more improved when, on the other hand, the average thickness T (nm) of the outermost layer is not more than 100.0 nm.
  • the average thickness T (nm) of the outermost layer can be controlled through, for example, the amount of addition of the material that forms the outermost layer. Specifically, the average thickness T (nm) of the outermost layer assumes an increasing trend as the amount of addition of the material that forms the outermost layer increases.
  • the average thickness T (nm) of the outermost layer is more preferably from 10.0 nm to 60.0 nm.
  • the outermost layer preferably contains a thermoplastic resin.
  • the content of the thermoplastic resin in the outermost layer may be, for example, from 50 mass % to 100 mass %.
  • thermoplastic resin can be exemplified by the following resins: styrenic resins, acrylic resins (for example, acrylate ester polymers and methacrylic acid polymers), olefin resins (for example, polyethylene resins and polypropylene resins), vinyl chloride resins, polyvinyl alcohol, vinyl ether resins, N-vinyl resins, polyester resins, polyamide resins, and urethane resins.
  • resins styrenic resins, acrylic resins (for example, acrylate ester polymers and methacrylic acid polymers), olefin resins (for example, polyethylene resins and polypropylene resins), vinyl chloride resins, polyvinyl alcohol, vinyl ether resins, N-vinyl resins, polyester resins, polyamide resins, and urethane resins.
  • copolymers of these resins i.e., copolymers (for example, styrene-acrylic resins and styrene-butadiene resins) provided by the insertion of a freely selected repeat unit into an aforementioned resin.
  • the thermoplastic resin preferably includes a styrene-acrylic resin.
  • a copolymer of at least one kind of styrenic monomers and at least one kind of (meth)acrylic monomers is also a preferred embodiment of this styrene-acrylic resin.
  • styrenic monomers and (meth)acrylic monomers as indicated in the following can be favorably used to synthesize the styrene-acrylic resin.
  • styrenic monomer examples include styrene, alkylstyrenes (for example, ⁇ -methylstyrene, p-ethylstyrene, and 4-tert-butylstyrene), p-hydroxystyrene, m-hydroxystyrene, vinyltoluene, ⁇ -chlorostyrene, ⁇ -chlorostyrene, m-chlorostyrene, and p-chlorostyrene.
  • alkylstyrenes for example, ⁇ -methylstyrene, p-ethylstyrene, and 4-tert-butylstyrene
  • p-hydroxystyrene p-hydroxystyrene
  • m-hydroxystyrene vinyltoluene
  • ⁇ -chlorostyrene ⁇ -chlorostyrene
  • m-chlorostyrene m-
  • (meth)acrylic monomers are (meth)acrylic acid, (meth)acrylonitrile, alkyl (meth)acrylate esters, and hydroxyalkyl (meth)acrylate esters.
  • alkyl (meth)acrylate esters are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isobutyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.
  • hydroxyalkyl (meth)acrylate esters are 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.
  • the outermost layer includes a thermosetting resin in another preferred embodiment.
  • the content of this thermosetting resin in the outermost layer may be, for example, from 50 mass % to 100 mass %.
  • thermosetting resin is melamine resins, urea resins, and glyoxal resins.
  • the thermosetting resin preferably includes a melamine resin.
  • Melamine resin is, for example, the polycondensate of melamine and formaldehyde, and the monomer used to form a melamine resin is, for example, melamine.
  • the binder resin preferably includes a styrene-acrylic resin (more preferably a styrene-alkyl acrylate ester resin).
  • the content of the styrene-acrylic resin in the binder resin may be, for example, from 50 mass % to 100 mass %.
  • thermoplastic resin in the outermost layer can be suitably used as the monomer for synthesis of the styrene-acrylic resin.
  • the binder resin includes a polyester resin in another preferred embodiment.
  • the content of the polyester resin in the binder resin may be, for example, from 1 mass % to 10 mass % or from 50 mass % to 100 mass %.
  • the polyester resin can be obtained by the condensation polymerization or cocondensation polymerization of a heretofore known dibasic or at least tribasic carboxylic acid component with a dihydric or at least trihydric alcohol component.
  • ester for example, acid halide, anhydride, and lower alkyl ester
  • dibasic or at least tribasic carboxylic acid component for example, acid halide, anhydride, and lower alkyl ester
  • Lower alkyl here means an alkyl group having from 1 to 6 carbon atoms.
  • dibasic carboxylic acid component dibasic acids such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, malonic acid, and dodecenylsuccinic acid and their anhydrides and lower alkyl esters, and aliphatic unsaturated dicarboxylic acids, e.g., maleic acid, fumaric acid, itaconic acid, and citraconic acid.
  • dibasic acids such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, malonic acid, and dodecenylsuccinic acid and their anhydrides and lower alkyl esters
  • aliphatic unsaturated dicarboxylic acids e.g., maleic acid, fumaric acid, itaconic acid, and citraconic acid.
  • 1,2,4-benzenetricarboxylic acid and 1,2,5-benzenetricarboxylic acid and their lower alkyl esters can be used as the at least tribasic carboxylic acid component.
  • a single one of these carboxylic acid components may be used by itself or at least two of these may be used in combination.
  • dihydric or at least trihydric alcohol component are diols, bisphenols, and at least trihydric alcohols.
  • the dihydric alcohol component can be exemplified by the following compounds: alkylene glycols (ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol), alkylene ether glycols (polyethylene glycol and polypropylene glycol), alicyclic diols (1,4-cyclohexanedimethanol), bisphenols (bisphenol A), and alkylene oxide (ethylene oxide or propylene oxide) adducts on alicyclic diols.
  • alkylene glycols ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol
  • alkylene ether glycols polyethylene glycol and polypropylene glycol
  • alicyclic diols 1,4-cyclohexanedimethanol
  • bisphenols bisphenol A
  • alkylene oxide ethylene oxide or propylene oxide
  • the alkyl moiety of the alkylene glycol and alkylene ether glycol may be straight chain or branched.
  • An alkylene glycol having a branched structure can also preferably be used.
  • the at least trihydric alcohol component can be exemplified by the following compounds: glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol.
  • a single one of these alcohol components may be used by itself or at least two of these may be used in combination.
  • a monobasic acid such as acetic acid or benzoic acid and a monohydric alcohol such as cyclohexanol or benzyl alcohol may also be used for the purpose of adjusting the acid value or hydroxyl value.
  • polyester resin there are no particular limitations on the method for synthesizing the polyester resin, but, for example, a transesterification method or direct polycondensation method, as such or in combination, may be used.
  • the toner base particle may contain a wax.
  • a known wax can be used as this wax.
  • petroleum waxes as represented by paraffin waxes, microcrystalline waxes, and petrolatum, and derivatives thereof; montan wax and derivatives thereof; hydrocarbon waxes provided by the Fischer-Tropsch method, and derivatives thereof; polyolefin waxes as represented by polyethylene, and derivatives thereof; and natural waxes as represented by carnauba wax and candelilla wax, and derivatives thereof.
  • These derivatives also include oxides and block copolymers and graft modifications with vinyl monomer.
  • alcohols such as higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid, and their acid amides, esters, and ketones; hardened castor oil and derivatives thereof; plant waxes; and animal waxes.
  • a single one of these waxes may be used by itself or at least two of these may be used in combination.
  • An oxidation inhibitor may be added to these waxes in a range that does not influence the effects for the toner according to the present disclosure.
  • the content of the wax is preferably from 1.0 mass parts to 30.0 mass parts per 100.0 mass parts of the binder resin.
  • the melting point of the wax is preferably from 30° C. to 120° C. and more preferably from 60° C. to 100° C.
  • the wax preferably contains an ester compound.
  • This ester compound can be exemplified by esters between a monohydric alcohol and an aliphatic carboxylic acid or an ester between a monobasic carboxylic acid and an aliphatic alcohol, such as behenyl behenate, stearyl stearate, and palmityl palmitate; esters between a dihydric alcohol and an aliphatic carboxylic acid and esters between a dibasic carboxylic acid and an aliphatic alcohol, such as ethylene glycol distearate, dibehenyl sebacate, and hexanediol dibehenate; esters between a trihydric alcohol and an aliphatic carboxylic acid and esters between a tribasic carboxylic acid and an aliphatic alcohol, such as glycerol tribehenate; esters between a tetrahydric alcohol and an aliphatic carboxylic acid and esters between a tetrabasic carboxylic acid and an aliphatic alcohol, such as pen
  • the wax more preferably contains, from the standpoint of the balance between the durability and low-temperature fixability, an ester compound given by formula (7) or formula (8).
  • R 1 represents an alkylene group having from 1 to 6 (preferably from 2 to 6 and more preferably from 2 to 4) carbons and R 2 and R 3 each independently represent an alkyl group having from 11 to 26 (preferably from 11 to 25 and more preferably from 16 to 22) carbons.
  • This alkyl group may be a straight-chain alkyl group or branched alkyl group, but straight-chain alkyl groups are preferred.
  • ester compounds given by formulas (7) and (8) ethylene glycol distearate, in which R 1 is a C 2 alkylene group and R 2 and R 3 are C 17 straight-chain alkyl groups, is more preferred.
  • the content of the ester compound in the wax is preferably from 50 mass % to 100 mass % and more preferably from 70 mass % to 100 mass %. Coexistence between the durability and low-temperature fixability is more readily brought about when the ester compound content in the wax is in the indicated range.
  • the toner base particle may contain a colorant.
  • Known pigments and dyes can be used as the colorant. Pigments are preferred for the colorant from the standpoint of providing an excellent weathering resistance.
  • Cyan colorants can be exemplified by copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.
  • Magenta colorants can be exemplified by condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.
  • Yellow colorants can be exemplified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo-metal complexes, methine compounds, and allylamide compounds.
  • Black colorants can be exemplified by carbon black and by black colorants provided by color mixing using the aforementioned yellow colorants, magenta colorants, and cyan colorants to give a black color.
  • a single one of these colorants may be used by itself or a mixture of at least two of these may be used. These may also be used in solid solution form.
  • the content of the colorant is preferably from 1.0 mass parts to 20.0 mass parts per 100.0 mass parts of the binder resin.
  • the toner base particle may contain at least one selection from the group consisting of charge control agents and charge control resins.
  • a known charge control agent can be used as the charge control agent, wherein a charge control agent that provides a fast triboelectric charging speed and that can maintain a defined and stable triboelectric charge quantity is particularly preferred.
  • a charge control agent that exercises little polymerization inhibition and that is substantially free of material soluble in the aqueous medium is particularly preferred.
  • Charge control agents include charge control agents that control toner to negative charging and charge control agents that control toner to positive charging.
  • Charge control agents that control the toner to negative charging can be exemplified by monoazo metal compounds; acetylacetone-metal compounds; metal compounds of aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acids; aromatic oxycarboxylic acids, aromatic monocarboxylic acids, and aromatic polycarboxylic acids and their metal salts, anhydrides, and esters; phenol derivatives such as bisphenol; urea derivatives; metal-containing salicylic acid compounds; metal-containing naphthoic acid compounds; boron compounds; quaternary ammonium salts; calixarene; and charge control resins.
  • Charge control agents that control toner to positive charging can be exemplified by the following: guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium 1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and their onium salt analogues, such as phosphonium salts, and their lake pigments; triphenylmethane dyes and their lake pigments (the laking agent is exemplified by phosphotungstic acid, phosphomolybdic acid, phosphomolybdotungstic acid, tannic acid, lauric acid, gallic acid, ferricyanides, and ferrocyanides); metal salts of higher fatty acids; and charge control resins.
  • guanidine compounds imidazole compounds
  • quaternary ammonium salts such as tributylbenzylammonium 1-hydroxy-4-naphthosulf
  • metal-containing salicylic acid compounds are preferred and metal-containing salicylic acid compounds in which the metal is aluminum or zirconium are particularly preferred.
  • the charge control resin can be exemplified by polymers and copolymers having a sulfonic acid group, sulfonate salt group, or sulfonate ester group.
  • Polymer having a sulfonic acid group, sulfonate salt group, or sulfonate ester group is particularly preferably a polymer that contains at least 2 mass %, as the copolymerization ratio, of a sulfonic acid group-containing acrylamide-type monomer or sulfonic acid group-containing methacrylamide-type monomer, and more preferably is a polymer containing at least 5 mass % of same.
  • the charge control resin preferably has a glass transition temperature (Tg) from 35° C. to 90° C., a peak molecular weight (Mp) from 10,000 to 30,000, and a weight-average molecular weight (Mw) from 25,000 to 50,000.
  • Tg glass transition temperature
  • Mp peak molecular weight
  • Mw weight-average molecular weight
  • a single one of these charge control agents or charge control resins may be used by itself, or at least two of these may be used in combination.
  • the content of the charge control agent or charge control resin, per 100.0 mass parts of the binder resin, is preferably from 0.01 mass parts to 20.0 mass parts and is more preferably from 0.5 mass parts to 10.0 mass parts.
  • Inorganic Particles of, e.g., Silica, Used as External Additive The toner particle as such may be used as a toner, but is often used as toner after optional mixing with, e.g., an external additive, to attach same to the surface.
  • silica particles with a number-average particle diameter (D1) for the primary particles of at least 40.0 nm (preferably at least 80.0 nm) on the toner surface is preferred.
  • This D1 can be, for example, not greater than 200 nm. Any combination of these numerical value ranges may be used.
  • the content of the silica particles having a primary particle D1 of at least 40.0 nm, per 100 mass parts of the toner particle, is preferably from 0.1 mass parts to 4.0 mass parts and is more preferably from 0.2 mass parts to 3.5 mass parts.
  • the flowability and charging performance can be improved by the addition to the toner particle of silica particles as an external additive.
  • the primary particle diameter of the external additive be at least 40.0 nm, the inorganic particles then become fixed in the concave portions in the outermost layer and a stabilization of the charging performance and flowability is obtained even during long-term use.
  • Inorganic particles other than the aforementioned silica particles may be present on the toner surface.
  • Such inorganic particles can be exemplified by titanium oxide particles, alumina particles, silica particles having a primary particle diameter of less than 40.0 nm, and composite oxide particles of the preceding.
  • the silica particles can be exemplified by the dry silica and fumed silica produced by the vapor-phase oxidation of a silicon halide, and by the wet silica produced from water glass. Dry silica is preferred because dry silica contains little of the silanol group present on the surface and in the interior of silica particles and contains little Na 2 O and SO 3 2 ⁇ .
  • the dry silica may be a composite fine particle of silica and another metal oxide as produced by the use in the production process of a silicon halide compound in combination with a metal halide compound such as, for example, aluminum chloride or titanium chloride.
  • hydrophobed silica particles are more preferably used as the silica particles.
  • the treatment agent for this hydrophobic treatment of the silica particles can be exemplified by unmodified silicone varnishes, variously modified silicone varnishes, unmodified silicone oils, variously modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, and organotitanium compounds.
  • a single one of these treatment agents may be used by itself or at least two of these may be used in combination.
  • silica particles that have been treated with silicone oil are preferred.
  • the BET retention ratio of the toner which is measured by the method described below, is preferably from 65% to 100% and more preferably from 67% to 100%.
  • the durability during long-term use tends to be more improved when the BET retention ratio of the toner is in the range from 65% to 100%.
  • the low-temperature fixability and storability in severe environments can also be further improved.
  • the BET retention ratio of the toner can be controlled through, for example, the addition of inorganic particles having a primary particle D1 of at least 40.0 nm and through the attachment conditions for the external additive (temperature, time).
  • the method for producing the toner contains the following steps.
  • dispersing agent particles are attached to the surface of the toner base particle, material for formation of the outermost layer is added to the dispersion that contains this toner base particle, and the outermost layer is formed on the surface of the toner base particle.
  • the medium used during formation of the outermost layer is preferably an aqueous medium from the standpoint of preventing the elution of components contained in the toner base particle into the medium.
  • Dispersing agent particles are attached to the surface of the toner base particle in step (a).
  • the following are examples of methods for attaching the dispersing agent particles to the surface of the toner base particle: addition of the dispersing agent after toner base particles have been mechanically dispersed in the aqueous medium using a device that has a strong stirring capability; addition of toner base particles to an aqueous medium that contains the dispersing agent. Between these, the addition of toner base particles to an aqueous medium containing the dispersing agent is preferred because this enables a uniform dispersion of the toner base particles in the aqueous medium using little power.
  • a polymeric dispersing agent, surfactant, resin particles, or inorganic particles can be used without particular limitation as the dispersing agent.
  • the use of inorganic particles is preferred from the standpoints of preventing surface modification of the surface of the toner base particle and bringing about a high level of dispersion of the toner base particle in the medium (particularly an aqueous medium).
  • Particles of an inorganic compound, e.g., sodium phosphate or calcium chloride can be used as the inorganic particles.
  • the number-average particle diameter of the dispersing agent particles is preferably from 30 nm to 350 nm and more preferably is from 50 nm to 200 nm.
  • the amount of use of the dispersing agent particles, per 100 mass parts of the toner base particle, is preferably from 0.3 mass parts to 30 mass parts and more preferably from 0.5 mass parts to 10.0 mass parts.
  • the dispersing agent particles can be attached to the toner base particle surface by introducing the toner base particles and carrying out mechanical mixing with a stirring device.
  • the toner base particle is produced by the suspension polymerization method
  • an aqueous dispersion of toner base particles having dispersing agent particles attached to the surface is produced in the production process, and as a consequence this aqueous dispersion of toner base particles can also be used as such as a toner base particle dispersion. That is, a step of attaching dispersing agent particles to the toner base particle surface can be included in the step of producing toner base particles.
  • the outermost layer is formed on the toner base particle surface in step (b).
  • an outermost layer can be formed on the toner base particle surface by adding the material of the outermost layer to the toner base particle dispersion.
  • the aforementioned thermoplastic resins and the aforementioned thermosetting resins can be used as the material of the outermost layer.
  • the outermost layer can be formed, for example, by mixing a dispersion of the thermoplastic resin with the toner base particles to attach the thermoplastic resin to the surface of the toner base particles in the aqueous dispersion, and heating.
  • the outermost layer can be formed by mixing the monomer constituting the thermosetting resin with the toner base particle and developing the reaction at the surface of the toner base particle in the aqueous medium by heating.
  • the outermost layer covers areas where the dispersing agent particles attached in step (a) are attached and is formed in a film configuration on all or a portion of the toner base particle surface.
  • the temperature during formation of the outermost layer is preferably from 40° C. to 90° C. and is more preferably from 50° C. to 80° C. Formation of the outermost layer proceeds well by carrying out formation of the outermost layer in this temperature range.
  • step (c) the dispersing agent particles are removed from the toner base particle surface after the outermost layer has been formed.
  • the dispersing agent particles are inorganic particles, for example, removal from the toner base particle surface can be carried out by dissolving the inorganic particles using acid and subsequently performing filtration. Removal of the dispersing agent particles enables the shape of the dispersing agent particle to be formed into a concave portion shape in the outermost layer.
  • the concave portions in the toner particle surface are observed using a scanning probe microscope (SPM) and the following method.
  • SPM scanning probe microscope
  • An SI-DF20 (Al coated back side) from Seiko Instruments Inc. is used for the measurement cantilever and is operated in dynamic force mode.
  • the SPM is used after checking the accuracy in the depth direction pre-measurement using a pattern sample (100 nm ⁇ 5 nm) for accuracy checking.
  • Conductive two-sided tape is first applied to the sample stand, and the toner particles are sprayed onto this. The excess toner particles are removed from the sample stand by blowing with air. Using this sample, the toner particle surface is magnified to 1 ⁇ m ⁇ 1 ⁇ m using the SPM (product name: E-sweep, Hitachi High-Tech Science Corporation) and the concave portions in the outermost layer are observed.
  • SPM product name: E-sweep, Hitachi High-Tech Science Corporation
  • the mean surface roughness means the arithmetic average value, over the 1 ⁇ m ⁇ 1 ⁇ m, of the depth of the concave portions for measurement toward the center of the toner particle from the outermost surface of the outermost layer, and is designated the depth d 1 (nm) of the concave portions in the outermost layer in the present disclosure.
  • the depths from d 1 to d 50 of the concave portions for 50 toner particles are determined by this method, and the arithmetic average value of from d 1 to d 50 is taken to be the depth D (nm) of the concave portions.
  • the number of concave portions “n” that satisfy formulas (1) to (3) and the number of the oversized concave portions “N” are determined as follows.
  • the tilt-corrected measurement data provided by the aforementioned measurement is output; the long diameters a (nm) of the concave portions, the short diameters b (nm) of the concave portions, and the depths d (nm) of the concave portions in 1 ⁇ m ⁇ 1 ⁇ m are surveyed; and the number of concave portions “n 1 ” that satisfy formulas (1) to (3) and the number of oversized concave portions “N 1 ”, in each case per 1 ⁇ m ⁇ 1 ⁇ m of the toner particle surface, are counted.
  • n 1 to n 50 of concave portions satisfying formulas (1) to (3) and the numbers from N 1 to N 50 of oversized concave portions are counted for 50 toner particles using this method, and their arithmetic average values are designated the number of concave portions “n” and the number of oversized concave portions “N”, respectively.
  • the long diameter A of the concave portions and the short diameter B of the concave portions are determined as follows.
  • the tilt-corrected measurement data provided by the aforementioned measurement is output; the arithmetic average values of the long diameters of the concave portions and the short diameters of the concave portions per 1 ⁇ m ⁇ 1 ⁇ m of the toner particle surface are determined and are respectively designated the long diameter a 1 of the concave portions and the short diameter b 1 of the concave portions.
  • the long diameters from a 1 to a 50 of the concave portions and the short diameters from b 1 to b 50 of the concave portions are determined for 50 toner particles using this method, and their arithmetic average values are designated the long diameter A of the concave portions and the short diameter B of the concave portions, respectively.
  • the external additive was removed using the following procedure and the measurements of the concave portions by the methods described above were performed on the resulting toner particles.
  • a 61.5% aqueous sucrose solution is prepared by the addition of 160 g of sucrose (Kishida Chemical Co., Ltd.) to 100 mL of deionized water and dissolving while heating on a water bath. 31.0 g of this sucrose concentrate and 6 g of Contaminon N (product name) (a 10 mass % aqueous solution of a neutral pH 7 detergent for cleaning precision measurement instrumentation, including a nonionic surfactant, anionic surfactant, and organic builder, Wako Pure Chemical Industries, Ltd.) are introduced into a centrifugal separation tube to prepare a dispersion. 1.0 g of the toner is added to this dispersion, and clumps of the toner are broken up using, for example, a spatula.
  • the centrifugal separation tube is shaken with a shaker for 20 minutes at 300 strokes per minute (spm). After shaking, the solution is transferred over to a glass tube (50 mL) for swing rotor service, and separation is performed with a centrifugal separator using conditions of 3,500 rpm and 30 minutes.
  • the toner particles separated into the uppermost layer are recovered with, for example, a spatula.
  • the recovered toner particles are filtered using a reduced pressure filter and are then dried for at least one hour in a dryer.
  • the dried product is broken up with a spatula to yield toner particles.
  • the cross section of the toner particle is observed with a transmission electron microscope (TEM) using the following method.
  • the toner particles are first thoroughly dispersed in a normal temperature-curable epoxy resin followed by curing for 2 days in a 40° C. atmosphere. Thin-section samples with a thickness of 50 nm are sliced from the resulting cured material using a microtome equipped with a diamond blade, and ruthenium staining is performed using a vacuum staining device (Filgen, Inc.). The resulting sample is then magnified 100,000 ⁇ using a TEM (product name: Tecnai TF20XT electron microscope, FEI Company). The thickness (unit: nm) of the outermost layer is measured at four randomly selected locations on a single toner particle.
  • TEM product name: Tecnai TF20XT electron microscope, FEI Company
  • the weight-average particle diameter (D4) and number-average particle diameter (D1) of the toner, toner particle, and toner base particle (also referred to below as, for example, toner) is determined proceeding as follows.
  • the measurement instrument used is a “Coulter Counter Multisizer 3” (registered trademark, Beckman Coulter, Inc.), a precision particle size distribution measurement instrument operating on the pore electrical resistance method and equipped with a 100- ⁇ m aperture tube.
  • the measurement conditions are set and the measurement data are analyzed using the accompanying dedicated software, i.e., “Beckman Coulter Multisizer 3 Version 3.51” (Beckman Coulter, Inc.).
  • the measurements are carried out in 25,000 channels for the number of effective measurement channels.
  • the aqueous electrolyte solution used for the measurements is prepared by dissolving special-grade sodium chloride in deionized water to provide a concentration of 1.0% and, for example, “ISOTON II” (Beckman Coulter, Inc.) can be used.
  • the dedicated software is configured as follows prior to measurement and analysis.
  • the total count number in the control mode is set to 50,000 particles; the number of measurements is set to 1 time; and the Kd value is set to the value obtained using “standard particle 10.0 m” (Beckman Coulter, Inc.).
  • the threshold value and noise level are automatically set by pressing the “threshold value/noise level measurement button”.
  • the current is set to 1,600 ⁇ A; the gain is set to 2; the electrolyte solution is set to ISOTON II; and a check is entered for the “post-measurement aperture tube flush”.
  • the bin interval is set to logarithmic particle diameter; the particle diameter bin is set to 256 particle diameter bins; and the particle diameter range is set to 2 ⁇ m to 60 ⁇ m.
  • the specific measurement procedure is as follows.
  • 3.3 L of deionized water is introduced into the water tank of the ultrasound disperser and 2.0 mL of Contaminon N is added to this water tank.
  • the beaker described in (2) is set into the beaker holder opening on the ultrasound disperser and the ultrasound disperser is started.
  • the vertical position of the beaker is adjusted in such a manner that the resonance condition of the surface of the aqueous electrolyte solution within the beaker is at a maximum.
  • aqueous electrolyte solution within the beaker set up according to (4) is being irradiated with ultrasound
  • 10 mg of the, e.g., toner is added to the aqueous electrolyte solution in small aliquots and dispersion is carried out.
  • the ultrasound dispersion treatment is continued for an additional 60 seconds.
  • the water temperature in the water tank is controlled as appropriate during ultrasound dispersion to be from 10° C. to 40° C.
  • the aqueous electrolyte solution prepared in (5) and containing, e.g., dispersed toner, is dripped into the roundbottom beaker set in the sample stand as described in (1) with adjustment to provide a measurement concentration of 5%. Measurement is then performed until the number of measured particles reaches 50,000.
  • the measurement data is analyzed by the dedicated software provided with the instrument and the weight-average particle diameter (D4) and the number-average particle diameter (D1) are calculated.
  • the “average diameter” on the “analysis/volumetric statistical value (arithmetic average)” screen is the weight-average particle diameter (D4).
  • the “average diameter” on the “analysis/numerical statistical value (arithmetic average)” screen is the number-average particle diameter (D1).
  • the volume-average diameter of the particles in the thermoplastic resin dispersion is measured using a Zetasizer Nano-ZS (Malvern Instruments Ltd.).
  • a measurement sample is first prepared by diluting the thermoplastic resin dispersion to be measured with water to a solid-liquid ratio of 0.10 mass % ( ⁇ 0.02 mass %), and this is introduced into a quartz cell, which is installed in the measurement section.
  • the refractive index of the thermoplastic resin and the refractive index and viscosity of the dispersing medium are input for the measurement conditions, and measurement is carried out in the range from 0.3 nm to 10.0 ⁇ m.
  • the glass transition temperature (Tg) of, e.g., the toner base particle or outermost layer material is measured using a “Q1000” differential scanning calorimeter (TA Instruments) in accordance with ASTM D 3418-82.
  • the melting points of indium and zinc are used for temperature correction in the instrument detection section, and the heat of fusion of indium is used for correction of the amount of heat.
  • a 10 mg sample is exactly weighed out and this is introduced into an aluminum pan; an empty aluminum pan is used for reference.
  • the measurement is run at a ramp rate of 10° C./min in the measurement temperature range from 30° C. to 200° C.
  • heating is carried out to 200° C., followed by cooling to 30° C. at a ramp down rate of 10° C./min and then reheating.
  • the change in the specific heat in the temperature range of from 40° C. to 100° C. is obtained in this second heating process.
  • the glass transition temperature (Tg) is taken to be the point at the intersection between the differential heat curve and the line for the midpoint for the baselines for prior to and subsequent to the appearance of the change in the specific heat.
  • the BET specific surface area of the toner is measured in accordance with JIS Z 8830 (2001).
  • the specific measurement procedure is as follows.
  • the “TriStar 3000 Version 4.00” dedicated software provided with this instrument is used to set the measurement conditions and analyze the measurement data.
  • a vacuum pump, nitrogen gas line, and helium gas line are connected to the instrument.
  • the value calculated by the BET multipoint method using nitrogen gas as the adsorption gas is used as the BET specific surface area in the present disclosure.
  • the BET specific surface area is specifically determined as follows.
  • nitrogen gas is adsorbed on the sample (toner) and the equilibration pressure P (Pa) within the sample cell and the amount of nitrogen adsorption Va (mol ⁇ g ⁇ 1 ) by the sample are measured at this point.
  • the adsorption isotherm is obtained using the relative pressure Pr, which is the value provided by dividing the equilibration pressure P (Pa) within the sample cell by the saturation vapor pressure of nitrogen Po (Pa), for the horizontal axis and using the amount of nitrogen adsorption Va (mol ⁇ g ⁇ 1 ) for the vertical axis.
  • Pr/Va (1 ⁇ Pr ) 1/( Vm ⁇ C )+( C ⁇ 1) ⁇ Pr /( Vm ⁇ C )
  • C is the BET parameter and is a variable that changes with the type of measurement sample, the type of adsorption gas, and the adsorption temperature.
  • the BET equation can be rendered as a straight line, with a slope of (C ⁇ 1)/(Vm ⁇ C) and an intercept of 1/(Vm ⁇ C), by using Pr for the X-axis and Pr/Va(1 ⁇ Pr) for the Y-axis.
  • the value of the slope of this straight line and the value of its intercept can be calculated by plotting the measured values of Pr and the measured values of Pr/Va(1 ⁇ Pr) on a graph and generating a straight line by the least-squares method.
  • Vm and C can be calculated by solving the aforementioned simultaneous equations for the slope and intercept.
  • the BET specific surface area S (m 2 ⁇ g ⁇ 1 ) of the sample is then calculated using the following formula, the Vm calculated as above, and the molecular cross-sectional area of the nitrogen molecule (0.162 nm 2 ).
  • S Vm ⁇ N ⁇ 0.162 ⁇ 10 ⁇ 18
  • N is Avogadro's number (mol ⁇ 1 ).
  • the procedure for calculating Vm is described in the following.
  • the procedure for determining Vm using this instrument is carried out according to the “TriStar 3000 Instruction Manual V4.0” provided with the instrument, and the measurement is specifically carried out using the following procedure.
  • the sample is introduced into this sample cell using a funnel.
  • the sample amount is adjusted as appropriate in accordance with the specific gravity and particle diameter of the sample; for toner, approximately 1.0 g is introduced.
  • the sample cell loaded with the sample is set in a “Vacuprep 061 Pretreatment Apparatus” (Shimadzu Corporation) connected to a vacuum pump and nitrogen gas line and vacuum degassing is continued for about 10 hours at 23° C.
  • This vacuum degassing is performed by gradually degassing while adjusting the valve in order to avoid suctioning sample into the vacuum pump.
  • the pressure in the cell gradually drops as degassing proceeds and approximately 0.4 Pa (approximately 3 millitorr) is finally reached.
  • nitrogen gas is gradually introduced and the interior of the sample cell is returned to atmospheric pressure and the sample cell is removed from the pretreatment apparatus.
  • the mass of this sample cell is exactly weighed and the precise mass of the toner is calculated from the difference from the tare mass.
  • the sample cell is closed with a rubber stopper during weighing in order to prevent the sample in the sample cell from being contaminated with, for example, moisture in the atmosphere.
  • Measurement of the free space in the sample cell including the connection fixtures is then performed.
  • the volume of the sample cell is measured at 23° C. using helium gas; then, after the sample cell has been cooled with liquid nitrogen, the volume of the sample cell is similarly measured using helium gas; and the free space is calculated converting from the difference in these volumes.
  • the saturation vapor pressure Po (Pa) of the nitrogen is automatically measured separately using the Po tube built into the instrument.
  • the sample cell is cooled with liquid nitrogen while vacuum degassing is continued. After this, nitrogen gas is admitted in stages into the sample cell and the nitrogen molecules are adsorbed to the sample.
  • P (Pa) equilibration pressure
  • the relative pressure Pr points for data collection are set at a total of six points, i.e., 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30.
  • a straight line is generated by the least-squares method from the obtained measurement data and Vm is calculated from the slope and intercept of this straight line. Using this value of Vm, the BET specific surface area of the toner is calculated as described above.
  • the type of resin is identified for the resin in the outermost layer using time-of-flight secondary ion mass spectrometry (TOF-SIMS).
  • TOF-SIMS time-of-flight secondary ion mass spectrometry
  • the resin type for the binder resin and the structure of the ester wax compound in the wax are identified using nuclear magnetic resonance spectroscopy ( 1 H-NMR) [400 MHz, CDCl 3 , room temperature (25° C.)] or pyrolysis GCMS.
  • methylation reagent 10% methanol solution of tetramethylammonium hydroxide
  • the number-average primary particle diameter of the external additive is determined using a scanning electron microscope (SEM).
  • the toner surface is observed using these conditions and the particle diameter of the external additive is determined. This procedure is repeated and the arithmetic average value for 200 is determined.
  • toner and toner production method according to the present disclosure are more particularly described by the examples provided below. However, these in no way limit the present disclosure. Unless specifically indicated otherwise, “parts” in the examples and comparative examples is on a mass basis in all instances.
  • the temperature of the polymerizable monomer composition was reduced to 15° C., followed by the admixture of 6.0 parts of tertiary-butyl peroxypivalate as polymerization initiator and introduction into the aforementioned aqueous solution.
  • An emulsion of the polymerizable monomer composition was prepared by exposure for 13 minutes (I second intermittent, maintenance of 25° C.) to ultrasound from a high-output ultrasound homogenizer (VCX-750).
  • thermoplastic resin dispersion 1 of a styrene-acrylic resin that would provide the outermost layer material.
  • This thermoplastic resin dispersion was then separated at 16,500 rpm for 1 hour using a centrifugal separator, and the supernatant was removed.
  • thermoplastic resin dispersion 1 having a solids concentration of 20.0 mass %.
  • the volume-average diameter of the particles in the thermoplastic resin dispersion 1 was measured at 25 nm, and the Tg was 69° C.
  • thermoplastic resin dispersion 2 was produced proceeding as in the method for producing the thermoplastic resin dispersion 1, but changing the amount of sodium dodecyl sulfate as indicated in Table 1 and changing the composition of the polymerizable monomer composition as indicated below.
  • the volume-average diameter of the particles in the thermoplastic resin dispersion 2 and Tg are given in Table 1.
  • thermoplastic resin dispersion 3 was produced proceeding as in the method for producing the thermoplastic resin dispersion 1, but changing, as indicated in Table 1, the amount of sodium dodecyl sulfate in the method for producing thermoplastic resin dispersion 1.
  • the volume-average diameter of the particles in the thermoplastic resin dispersion 3 and Tg are given in Table 1.
  • a styrene-acrylic resin 1 was synthesized by continuously adding 50.0 parts of a 2.0% xylene solution of t-butyl hydroperoxide dropwise to the system over 4.5 hours and, after cooling, separating and removing the solvent.
  • the weight-average molecular weight Mw was 14,500, and Tg was 65° C.
  • the system was subjected to nitrogen substitution by a pressure-reduction process, after which heating was carried out to 210° C. and a reaction was run for 5 hours while introducing nitrogen and removing the produced water. Then, while continuing to stir, the temperature was gradually raised to 230° C. under reduced pressure, and a polyester resin 1 was synthesized by reaction for an additional 3 hours.
  • the weight-average molecular weight Mw was 9,500, and Tg was 68° C.
  • the resulting kneaded material was cooled and was coarsely pulverized to 1 mm and below using a hammer mill to yield a coarse pulverizate.
  • a fine pulverizate of about 5 ⁇ m was then obtained from the resulting coarse pulverizate using a Turbo Mill from Turbo Kogyo Co., Ltd., followed by cutting the fines and coarse powder using a Coanda effect-based multi-grade classifier to obtain the toner base particle 1.
  • Toner base particle 1 had a number-average particle diameter (D1) of 5.4 ⁇ m, a weight-average particle diameter (D4) of 6.8 ⁇ m, and a Tg of 58° C.
  • toner base particle 1 200.0 parts was introduced into aqueous medium 1 and dispersion was carried out for 30 minutes at a temperature of 40° C. while rotating at 7,000 rpm using a T.K. Homomixer. Deionized water was added to adjust the toner base particle concentration in the dispersion to 20.0%, thus providing toner base particle dispersion 1.
  • Aqueous media 2 to 5 and toner base particle dispersions 2 to 5 were produced proceeding as in the method for producing the toner base particle dispersion 1, but changing, as shown in Table 2, the amounts of the sodium phosphate and calcium chloride used for the aqueous medium 1 in the method for producing the toner base particle dispersion 1.
  • the resulting kneaded material was cooled and was coarsely pulverized to 1 mm and below using a hammer mill to yield a coarse pulverizate.
  • a fine pulverizate of about 5 ⁇ m was then obtained from the resulting coarse pulverizate using a Turbo Mill from Turbo Kogyo Co., Ltd., followed by cutting the fines and coarse powder using a Coanda effect-based multi-grade classifier to obtain the toner base particle 2.
  • Toner base particle 2 had a number-average particle diameter (D1) of 5.6 ⁇ m, a weight-average particle diameter (D4) of 7.0 ⁇ m, and a Tg of 60° C.
  • toner base particle 2 200.0 parts was introduced into aqueous medium 1 and dispersion was carried out for 30 minutes at a temperature of 40° C. while rotating at 7,000 rpm using a T.K. Homomixer. Deionized water was added to adjust the toner base particle concentration in the dispersion to 20.0%, thus providing toner base particle dispersion 6.
  • This material was then held at 65° C. and a polymerizable monomer composition 1 was prepared by dissolving and dispersing to uniformity at 500 rpm using a T.K. Homomixer.
  • the polymerizable monomer composition 1 was introduced into the aqueous medium 6 and 7.0 parts of the polymerization initiator t-butyl peroxypivalate was added. Granulation was performed for 10 minutes under these conditions while maintaining 12,000 rpm with the stirrer.
  • the high-speed stirrer was replaced with a stirrer equipped with a propeller impeller and polymerization was carried out for 5.0 hours while maintaining 70° C. and stirring at 150 rpm.
  • An additional polymerization reaction was run by raising the temperature to 85° C. and heating for 2.0 hours.
  • Deionized water was added to adjust the toner base particle concentration in the dispersion to 20.0%, thus yielding toner base particle dispersion 7 in which toner base particle 3 was dispersed.
  • Toner base particle 3 had a number-average particle diameter (D1) of 5.4 ⁇ m, a weight-average particle diameter (D4) of 6.2 ⁇ m, and a Tg of 56° C.
  • a reactor holding 400.0 parts of deionized water was held at 30° C., after which dilute hydrochloric acid was added to adjust the pH of the aqueous medium to 4.0. After the pH had been adjusted, the following materials were introduced and dissolution was carried out to obtain aqueous medium 7.
  • toner base particle 1 200.0 parts was added to aqueous medium 7 and the reactor was stirred for 1 hour at a rate of 200 rpm. Deionized water was then added to adjust the toner base particle concentration in the dispersion to 20.0%, thus yielding a toner base particle dispersion 8 in which toner base particle 1 was dispersed.
  • a reactor holding 400.0 parts of deionized water was held at 30° C., after which dilute hydrochloric acid was added to adjust the pH of the aqueous medium to 4.0. After the pH had been adjusted, the following material was introduced to obtain aqueous medium 8.
  • toner base particle 1 200.0 parts was added to aqueous medium 8 and the reactor was stirred for 1 hour at a rate of 200 rpm. Deionized water was then added to adjust the toner base particle concentration in the dispersion to 20.0%, thus yielding a toner base particle dispersion 9 in which toner base particle 1 was dispersed.
  • a reactor holding 400.0 parts of deionized water was held at 30° C., after which dilute hydrochloric acid was added to adjust the pH of the aqueous medium to 4.0. After the pH had been adjusted, the following material was introduced to obtain aqueous medium 9.
  • toner base particle 1 was added to aqueous medium 9 and the reactor was stirred for 1 hour at a rate of 200 rpm. Deionized water was then added to adjust the toner base particle concentration in the dispersion to 20.0%, thus yielding a toner base particle dispersion 10 in which toner base particle 1 was dispersed.
  • a reactor holding 400.0 parts of deionized water was held at 30° C., after which dilute hydrochloric acid was added to adjust the pH of the aqueous medium to 4.0. After the pH had been adjusted, the following material was introduced to obtain aqueous medium 10.
  • toner base particle 2 200.0 parts was added to aqueous medium 10 and the reactor was stirred for 1 hour at a rate of 200 rpm. Deionized water was then added to adjust the toner base particle concentration in the dispersion to 20.0%, thus yielding a toner base particle dispersion 11 in which toner base particle 2 was dispersed.
  • Toner Base Particle Dispersion 12 Production Example Preliminary External Addition to Toner Base Particle 2
  • mixer FM-10B Henschel mixer from Nippon Coke & Engineering Co., Ltd.
  • toner base particle 4 200.0 parts was added to aqueous medium 10 and the reactor was stirred for 1 hour at a rate of 200 rpm. Deionized water was then added to adjust the toner base particle concentration in the dispersion to 20.0%, thus yielding a toner base particle dispersion 12 in which toner base particle 4 was dispersed.
  • the polymerizable monomer composition 1 was introduced into the aqueous medium 11 and 7.0 parts of the polymerization initiator t-butyl peroxypivalate was added. Granulation was performed for 10 minutes under these conditions while maintaining 12,000 rpm with the stirrer.
  • the high-speed stirrer was replaced with a stirrer equipped with a propeller impeller and a polymerization reaction was run at 80° C. while stirring at 150 rpm. After the polymerization conversion had reached approximately 100%, 2.0 parts of methyl methacrylate, as polymerizable monomer for the outermost layer, and 0.1 parts of 2,2-azobis(2-methyl-N-(2-hydroxyethyl)propionamide) (VA086, Wako Pure Chemical Industries, Ltd.) dissolved in 10.0 parts of deionized water were added while maintaining the same polymerization temperature. The temperature was then raised to 90° C. and a polymerization reaction was run while heating for 3.0 hours. Deionized water was added to adjust the toner base particle concentration in the dispersion to 20.0%, thus yielding a toner base particle dispersion 13 in which toner base particle 5 was dispersed.
  • VA086, Wako Pure Chemical Industries, Ltd. 2,2-azobis(2-methyl-N-(2-hydroxyethyl)propionamide
  • Toner base particle 5 had a number-average particle diameter (D1) of 5.6 ⁇ m, a weight-average particle diameter (D4) of 6.4 m, and a Tg of 57° C.
  • the system was subjected to nitrogen substitution by a pressure-reduction process, after which heating was carried out to 210° C. and a reaction was run for 5 hours while introducing nitrogen and removing the produced water. Then, while continuing to stir, the temperature was gradually raised to 230° C. under reduced pressure, and a polyester resin 2 was synthesized by reaction for an additional 3 hours.
  • the weight-average molecular weight Mw was 8,200, and Tg was 54° C.
  • the system was subjected to nitrogen substitution by a pressure-reduction process, after which heating was carried out to 210° C. and a reaction was run for 5 hours while introducing nitrogen and removing the produced water. Then, while continuing to stir, the temperature was gradually raised to 230° C. under reduced pressure, and the polyester resin 3 was synthesized by reaction for an additional 3 hours.
  • the weight-average molecular weight Mw was 7,800, and Tg was 40° C.
  • the resulting kneaded material was cooled and was coarsely pulverized to not greater than 1 mm using a hammer mill to yield a coarse pulverizate.
  • a fine pulverizate of about 5 ⁇ m was then obtained from the resulting coarse pulverizate using a Turbo Mill from Turbo Kogyo Co., Ltd., followed by cutting the fines and coarse powder using a Coanda effect-based multi-grade classifier to obtain the toner base particle 6.
  • Toner base particle 6 had a number-average particle diameter (D1) of 5.8 ⁇ m, a weight-average particle diameter (D4) of 7.1 ⁇ m, and a Tg of 62° C.
  • toner base particle 6 200.0 parts was introduced into aqueous medium 8 and dispersion was carried out for 30 minutes at a temperature of 40° C. while rotating at 7,000 rpm using a T.K. Homomixer. Deionized water was added to adjust the toner base particle concentration in the dispersion to 20.0%, thus providing toner base particle dispersion 14.
  • Toner base particle 7 was obtained proceeding as for toner base particle 1, but without using the ethylene glycol distearate. Toner base particle dispersion 15 was then obtained proceeding as for toner base particle dispersion 1.
  • Toner base particle 8 was obtained proceeding as for toner base particle 1, but using 1,6-hexanediol dilaurate in place of the ethylene glycol distearate.
  • Toner base particle dispersion 16 was then obtained proceeding as for toner base particle dispersion 1.
  • Toner base particle 9 was obtained proceeding as for toner base particle 1, but using the ester compound given by CH 3 (CH 2 ) 25 CO(CH 2 ) 2 COO(CH 2 ) 25 CH 3 in place of the ethylene glycol distearate. Toner base particle dispersion 17 was then obtained proceeding as for toner base particle dispersion 1.
  • the pH of the resulting mixture was then adjusted to 7.0 using a 1 mol/L aqueous NaOH solution, and the temperature of the mixture was brought to 30° C. and holding was subsequently carried out for 1.0 hour while mixing using the propeller impeller at 200 rpm. Then, while stirring with the propeller impeller, the temperature was raised to 80° C. at a rate of 1° C./min and holding was carried out for 2 hours.
  • the temperature of the contents was thereafter cooled to normal temperature (approximately 25° C.); the pH was then adjusted to 1.5 with 1 mol/L hydrochloric acid and stirring was carried out for 1.0 hour; and filtration while washing with deionized water subsequently yielded a toner particle 1 having a styrene-acrylic thermoplastic resin in the outermost layer.
  • Toner particles 2 to 12 and 14 to 20 were produced proceeding as in the Toner Particle 1 Production Example, but changing the type of toner base particle dispersion and the type and amount of the thermoplastic resin dispersion in the Toner Particle 1 Production Example to that indicated in Table 3.
  • the temperature of the mixture was then brought to 30° C. and holding was subsequently carried out for 1.0 hour while mixing using a propeller impeller at 200 rpm. Then, while stirring with the propeller impeller, the temperature was raised to 80° C. at a rate of 1° C./min and holding was carried out for 2 hours. This was followed by adjusting the pH of the resulting mixture to 7.0 using a 1 mol/L aqueous NaOH solution.
  • the temperature of the contents was thereafter cooled to normal temperature (approximately 25° C.); the pH was then adjusted to 1.5 with 1 mol/L hydrochloric acid and stirring was carried out for 1.0 hour; and filtration while washing with deionized water subsequently yielded a toner particle 13 having a melamine thermosetting resin in the outermost layer.
  • toner base particle dispersion 8 500.0 parts was introduced into a reactor and the temperature was raised to 80° C. at a rate of 1° C./min while stirring at 100 rpm. After the temperature had been raised, stirring was continued for 2 hours using conditions of 80° C. and 100 rpm. The pH of the resulting mixture was then adjusted to 7.0 using a 1 mol/L aqueous NaOH solution.
  • Toner particles 22 to 24 and 26 were produced proceeding as in the Toner Particle 21 Production Example, but changing the type and amount of the toner base particle dispersion and the production temperature in the Toner Particle 21 Production Example to that indicated in Table 3.
  • toner base particle dispersion 12 was introduced into a reactor and the temperature was raised to 80° C. at a rate of 1° C./min while stirring at 100 rpm. After the temperature had been raised, stirring was continued for 2 hours using conditions of 80° C. and 100 rpm. The pH of the resulting mixture was then adjusted to 7.0 using a 1 mol/L aqueous NaOH solution. After the temperature of the contents had then been cooled to normal temperature (approximately 25° C.), filtration and washing were carried out five times to yield a toner particle 25 that had a melamine thermosetting resin in the outermost layer and that had the pre-externally-added acrylic monodisperse particles fixed to the surface.
  • the pre-externally-added acrylic monodisperse particles on the toner base particle surface were then removed.
  • the melamine thermosetting resin formed in the outermost layer is tightly fixed to the toner base particle surface, while the pre-externally-added acrylic monodisperse particles are fixed to the surface by a weak force.
  • the pre-externally-added particles can be removed by the application of an external force even after the outermost layer has been formed.
  • toner particle 25 was first dispersed in a mixed aqueous solution including a 61.5% aqueous sucrose solution and a 10.0% neutral aqueous detergent solution for cleaning precision measurement instrumentation, including a nonionic surfactant and an anionic surfactant.
  • a treatment of shaking 300 times in 1 minute was then performed using a shaker, after which the thusly treated toner particle 25 was dispersed in the aforementioned mixed aqueous solution and was subjected to a treatment in which ultrasound was applied for 10 minutes at an electrical output of 120 W.
  • the execution of five cycles of filtration and washing yielded a toner particle 25 that had a melamine thermosetting resin in the outermost layer, and from which the acrylic monodisperse particles had been removed.
  • toner base particle dispersion 14 500.0 parts was introduced into a reactor and the temperature was raised to 70° C. at a rate of 1° C./min while stirring at 100 rpm. Immediately after the temperature in the reactor reached 55° C. during the temperature ramp up process, the pH of toner base particle dispersion 14 was adjusted to 9.0 by adding a 1 mol/L aqueous NaOH solution to the reactor. This was followed by continuing to stir for 2 hours using conditions of 70° C. and 100 rpm.
  • toner particle 1 The external additives indicated below were added to 100 parts of toner particle 1 and mixing was carried out for 10 minutes at a peripheral velocity of 32 m/s using an FM mixer (Nippon Coke & Engineering Co., Ltd.); toner 1 was obtained by removing the coarse particles using a mesh with an aperture of 45 ⁇ m.
  • Toners 2 to 18 and 21 to 27 were produced proceeding as in the Toner 1 Production Example.
  • toner particle 19 was obtained by removing the coarse particles using a mesh with an aperture of 45 ⁇ m.
  • toner 20 was obtained by removing the coarse particles using a mesh with an aperture of 45 ⁇ m.
  • the potential in charging, transfer, and so forth was made reversible through connection to an external high-voltage power source and image formation was thus made possible with a positive-charging or a negative-charging toner as produced in the present instance.
  • the process speed was also made 210 mm/sec.
  • a commercial 040H (cyan) toner cartridge (Canon, Inc.) was used as the process cartridge.
  • the product toner was removed from the interior of the cartridge; cleaning with an air blower was performed; and 165 g of a toner as described above was loaded.
  • the product toner was removed at each of the yellow, magenta, and black stations, and the evaluations were performed with the yellow, magenta, and black cartridges installed, but with the remaining toner amount detection mechanism inactivated.
  • the BET retention ratio was calculated using the following formula—where V ini is the BET specific surface area prior to the evaluation in the paper-feed durability test and V end is the BET specific surface area after the 20,000-sheet paper-feed durability test—and was used to evaluate the toner durability.
  • BET retention ratio (%) V end /V ini ⁇ 100
  • the fixing unit was detached from the modified LBP-712Ci laser printer (Canon, Inc.). Using the loaded toner, an unfixed toner image (0.9 mg/cm 2 ) with a length of 2.0 cm ⁇ width of 15.0 cm was subsequently formed on image-receiving paper (Office Planner 64 g/m 2 , Canon, Inc.) at a location 1.0 cm from the leading edge with respect to the paper feed direction. The detached fixing unit was then modified to enable adjustment of the fixation temperature and process speed. This was used to carry out a fixing test on the unfixed image.
  • image-receiving paper Office Planner 64 g/m 2 , Canon, Inc.
  • the low temperature-side fixing onset point was measured by carrying out fixing of the unfixed image at each temperature starting from an initial temperature of 110° C. and increasing the set temperature sequentially in 5° C. increments.
  • This low temperature-side fixing onset point is the lowest temperature at which there are three or fewer occurrences of image exfoliation with a diameter of at least 150 ⁇ m, when the surface of the fixed image has been rubbed five times at a speed of 0.2 m/s using lens-cleaning paper (Dusper K-3) carrying a load of 4.9 kPa (50 g/cm 2 ).
  • This image exfoliation assumes an increasing trend when a strong fixing has not been executed.
  • the evaluation criteria are as follows.

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